I am recently working on a project of building a Online Judge using Java and my minimum target was at least to make sure that it can detect the four most popular verdicts in Competitive Programming world. I somehow managed to implement AC, WA, TLE. But I am at a loss how to handle Runtime Error. For most of the cases, my program takes RE as TLE. I am just curious to know how can one determine Runtime Error effectively. I would love to have some idea about it and which can be a better a platform than CF community!

I'm afraid I could not get the meaning of "output" in your comment. what did you mean by output? Can you please elaborate ?

If you mean by "output" the output of the program submitted by the client against judge data, then what about the case when the code will get a TLE? Because in this case the output will also be a null, I think. Am I right?

No. During TLE you will get partial output and it will cross problem time limit. But During Runtime Error No output will be generated that means it will return null value. So at first check what your compile returns. if the result is totally null then it is run time error else if the total execution time is crossed problem time limit then tle .